The present invention pertains to a numerically controlled surface-processing machine for processing of workpieces, such as blades on knives, scissors, hand tools or the like, in particular it pertains to a grinding machine, a polishing machine or a lapping machine, with a clamping device for the workpieces and with a memory-programmable computer for the numerical control. In addition, the invention pertains to a method for preparation of a numerically controlled surface-processing process with a machine of this type.
As a preparation for numerically controlled surface-processing, in particular for grinding of a workpiece, it is known how to prepare a working plan from the design drawing with a sequence of required processing steps. The working plan, which contains the geometric information for the workpiece from the drawing, is converted into a control program, wherein the construction and technological conditions of the surface-processing machine to be used for the processing are taken into account in the form of a clamping and tool plan. A program of this kind is prepared according to defined programming rules that are standardized internationally, e.g., by German Standard DIN 66025. This preparation of the numerically controlled surface-processing is very complicated. In certain processing jobs, e.g., the processing of rough blanks from a supplier, a design drawing may not be available in a timely manner, if at all, under certain circumstances. In this case, the supplied rough blanks must be measured first, and any potential tolerance problems must be taken into account. Another problem is that parts to be processed with identical contours may require a different control program in case of a slight deviation in the clamping, e.g., in their angular position with respect to the machine table.
During machine programming of the grinding, polishing or lapping, the programmer inputs the geometric and technological information into the system using a high-level programming language. From this data, the system, e.g., a memory-programmable computer of the system, calculates the corresponding subroutine with the various alignment and operating movements. Here, too, the step of information input is particularly complicated and time-intensive. The preparation for the work thus places strict demands on the qualification of the operator of the machine.
The present invention is based on the problem of improving a numerically controlled surface-processing machine of the stated kind and of improving the known method for preparation of a numerically controlled surface-processing process in such a way that the preparation for grinding can be simplified and shortened, while ensuring a good operating accuracy of the machine.
According to the invention, this is achieved with regard to the machine through the use of a numerically controlled surface-processing machine for processing of workpieces such as blades on knives, scissors, hand tools or the like, in particular for a grinding machine, a polishing machine or a lapping machine, which features the following components and characteristics:
a memory-programmable computer for numerical control,
a clamping device for the workpieces,
a sensor located at a distance from the clamping device,
wherein the sensor and the clamping device are controlled so that they can move relative to each other for acquisition of contour coordinates of a workpiece clamped in the clamping device in at least one spatial direction into a number of predefined positions,
a control device coupled to the sensor for processing of the determined coordinates that comprises:
a memory for point-by-point imaging of the coordinates,
means for interpolation of the determined coordinates in order to generate at least one continuous function for the contour profile of one coordinate in one spatial direction from at least one other coordinate in a second spatial direction,
an interface between the control device coupled with the sensor and the memory-programmable computer for transfer of the continuous function for the numerical control.
With regard to the aspect of technological manufacture, the problem underlying the invention is solved by a method for preparation of a numerically controlled surface processing process for workpieces, such as blades on knives, scissors, hand tools or the like, on a numerically controlled surface-processing machine that features a clamping device for the workpieces and a memory-programmable computer for the numerical control. Contour coordinates of a workpiece clamped in the clamping device are determined in a number of default positions by a sensor, and by means of a control device coupled with the sensor for processing of the determined coordinates, the coordinates are imaged point by point. Through interpolation of these coordinates, at least one continuous function for the contour profile of one coordinate is determined in one spatial direction from at least one other coordinate in a second spatial direction. This function is passed as an input parameter to the memory-programmable computer.
The machine according to the invention and the method according to the invention are thus designed for so-called workshop programming, and the final form of the program for numerical control of the grinding is defined by the operator of the machine. The workpiece geometry (contour) is acquired point by point by means of the sensor in the form of coordinates that are processed in the control device connected to the sensor to form at least one continuous function for the contour profile of one coordinate in one spatial direction from at least one other coordinate of a second spatial direction, and this is input, together with the point-wise function, into the memory-programmable computer for the numerical control via the interface. Thus, the preparation of the numerically controlled grinding of a new workpiece requires only little additional machine operating time so that the grinding machine according to the invention can also be used with high efficiency for single production and small batch production of workpieces with complicated contours, e.g. curved in all three spatial directions.
The memory-programmable computer can be designed so that the continuous function is saved directly as a desired value for the numerical control. In this case, a finished workpiece with a final contour to be manufactured can be clamped in the clamping device. Presuming that the workpieces to be processed next generally coincide in fundamental geometry and in clamping orientation with the finished workpiece, the grinding can be carried out by means of repetition of the stored desired value or of the control program that was prepared for the finished part.
Another possibility consists in designing the memory-programmable computer so that the continuous function is first stored as an actual value of the contour of the clamped tool, and then preferably, the function can be modifiedxe2x80x94for example, as described in detail belowxe2x80x94interactively into a desired-value function.
The invention will be explained in greater detail based on one embodiment example illustrated in the attached drawing illustrating a surface-processing machine and method.